#define _CRT_SECURE_NO_WARNINGS 1
#include<iostream>
#include<vector>
using namespace std;

class Solution {
public:
    int singleNumber(vector<int>& nums) {
        int value = 0;
        for (auto e : nums)
        {
            value ^= e;
        }
        return value;
    }
};

int main()
{
    vector<int> v1({1,1,2});
    Solution s1;
    cout << s1.singleNumber(v1) << endl;

    return 0;
}